Bruce McKinlay, a zoologist with the Department of Conservation, responded.

The heaviest bird in the New Zealand forest today is the night parrot,
the kakapo which can weigh between 2 and 2.5 kg.

The kakapo is also the
longest bird having a length including tail of about 63 cm. The heaviest
bird that you are likely to see in the New Zealand forest today is the
native pigeon or kereru which weighs about 650 grams and is about 51 cm
in length. Kaka which weigh between 500 and 575 grams and are about 45 cm
in length can still be seen in the forests in Fiordland and the West
Coast. The next biggest bird is one that you are more likely to hear
rather than see is the long tailed cuckoo which has a length of 40 cm and
a weight of about 125 grams.

The size and weight of these birds are however nothing compared to the
extinct moa and Haasts eagle. Based on calculations derived from femur
bones it has been estimated that the largest moa, Dinornis giganteus
weighed between 133 and 272 kg. Other moa species ranged in size from 16
to 247 kg.

Haasts eagle Harpagonis moorei is the largest known flying eagle.
Females weighed between 13-15 kg while males weighed about 10 kg. It had
a wingspan of about 2.4 to 2.6 metres-just slightly shorter than a
wandering albatross.

Going for a walk in the New Zealand forest is not as exciting as it might
have been seven hundred years ago.